visual
visual

세미나

  • HOME
  • >
  • 소식
  • >
  • 세미나
날짜 2016-09-21 16:00 
연사  
장소 E6-2. #2502(2nd fl.) 

Entanglement probe of two-impurity Kondo physics

 

4pm, Sep. 21 (Wed.), E6-2. #2502(2nd fl.)
Dr. Henrik Johannesson , University of Gothenburg (Sweden) and Beijing Computational Science Research Center (China)


The two-impurity Kondo model has bearings on a number of topical problems, from heavy-fermion physics to spin-based quantum computing. In this talk I will review what is known about the model and also present a novel approach to its study, initiated in a collaboration with A. Bayat, S. Bose, and P. Sodano [1]. Specifically, we propose that real-space properties of the model can be obtained from an effective spin model where two single-impurity Kondo spin chains are joined via an RKKY interaction between the two impurity spins. We then use the Density Matrix Renormalization Group (DMRG) to study its features, using two complementary quantum-entanglement measures, the negativity and the von Neumann entropy. This nonperturbative approach enables us to uncover the Kondo screening cloud and its enhancement in the limit of large ferromagnetic RKKY coupling, thus corroborating a long-standing conjecture of ”Kondo resonance narrowing" for effectively large impurity spins. In a follow-up work [2], we extended our approach to study the entanglement spectrum of the model, and obtained the Schmidt gap, i.e. the difference between the two largest eigenvalues of the reduced density matrix. The Schmidt gap is found to signal the quantum phase transition between the Kondo and RKKY phases, in effect serving as an order parameter, correctly predicting the known scaling exponent for the Kondo crossover length at the critical point. Time permitting, I will briefly discuss also some more recent applications of our approach, to the study of local quantum quenches [3], the entanglement structure of the two-channel Kondo model [4], and impurity quantum thermodynamics [5].

 

[1] A. Bayat et al., Phys. Rev. Lett. 109, 066403 (2012)
[2] A. Bayat et al., Nat. Comm. 5, 3784 (2014)
[3] A. Bayat et al., Phys. Rev. B 92, 155141 (2015)
[4] B. Alkurtass et al., Phys. Rev. B 93, 081106(R) (2016)
[5] A. Bayat et al., Phys. Rev. B 93, 201106(R) (2016)

Contact: Heung Sun Sim, Physics Dept., (hs_sim@kaist.ac.kr)

번호 날짜 연사 제목
공지 2025-02-24 16:00    2025년 봄학기 콜로키움 안내
공지 2025-02-27 16:00    2025년 봄 물리학과 특별세미나 (광학/응집물리 분야)
354 2019-09-27 14:30    Spin-charge conversion in topological insulators for spintronic applications file
353 2019-09-27 16:00    0D/1D/2D/3D III-V materials grown by MBE for Optelectronics file
352 2019-10-15 16:00    Moiré superlattices and graphene quasicrystal file
351 2019-10-16 16:00    Emergent black holes and monopoles from quantum fields file
350 2019-10-17 16:00    Top down manipulation of Waves : From Metamaterials, Correlated Disorder, Quantum Analogy, to Digital Processing file
349 2019-10-25 15:00    Physics Seminar file
348 2019-10-29 10:00    Unconventional Spin Transport in Quantum Materials file
347 2019-10-29 14:30    Quantum sensing file
346 2019-10-29 16:00    Particles and Gravity via String Geometry file
345 2019-10-31 10:00    Kondo meets Hubbard: Impurity physics for correlated lattices file
344 2019-11-01 14:30    Squeezing the best out of 2D materials file
343 2019-11-01 16:00    Electron transport through weak-bonded contact metal with low dimensional nano-material file
342 2019-11-05 16:00    Study on nanomaterials by the development of ultrahigh resolution laser-photoelectron microscopy (PEEM) file
341 2019-11-07 16:00    Integrated quantum photonics with solid-state quantum emitters file
340 2019-11-14 16:00    Semi-classical model of polariton propagation file
339 2019-11-20 16:00    Correlation between superconducting transition temperature and critical current density in irradiated iron-based superconductors file
338 2019-11-28 16:00    Generation of coherent EUV emissions using ultrashort laser pulses file
337 2019-12-03 16:00    Toward Quantum Materials with Correlated Oxides file
336 2019-12-05 16:00    Subwavelenth Photonic Devices: From Single Photon Sources to Solar Cell file
335 2019-12-13 13:00    Computational Material Designs: Current Status and Future Directions file